The project is designed to elucidate the role of xenobiotic-metabolizing enzymes in skin as mediators of the toxicity of environmental agents. Mixed-function oxidases, (including aryl hydrocarbon hydroxylase), glutathione S-transferase, UDP-glucuronosyltransferase and sulfotransferase activities are measured in whole skin, epidermal cells or subcellular fractions of epidermal cells from hairless mice (Hrs/J). Mixed function oxidase activities in Zymbal's glands from mice and rats were compared with those in skin sebaceous cells. Epidermal cell types high in xenobiotic metabolizing activity and/or cytochrome P-450 content are being identified. Changes in xenobiotic metabolism and/or in the content of mixed-function oxidase components after exposure (topical or systemic) of mice to various effectors such as ultraviolet radiation, polycyclic hydrocarbons, and steroids are being investigated.